Process of preparing holes for blasting.



W. H. MASON.

PROCESS OF PREPARING HOLES FOR BLASTING.

APPLICATION FILED JAN. 20. I915.

11 165 6910 Patented Dec. 28, 1915.

WITNESSES WILLIAM H. MASON, OF EASTON, PENNSYLVANIA.

-PROCESS OF PREPARING HOLES FOR, BLASTING.

Manner.

Specification of Letters E'atent.

Patented Dec, 2d, 1915 "Application. filed January 20, 1915. Serial Ito.3,295.

To all whom it may concern:

7 Be it known that 1, WILLIAM H. Mason, a citizen of the United States,and a resident of Easton, county of Northampton, and State ofPennsylvania, have invented certain new and useful Improvements inProcesses of Preparing Holes for Blasting, of which the followin is aspecification.

My inventlon relates to a rocess for the preparation of holes forblasting and is particularly applicable in carbonate rock, such as thevarious types of limestone, etc., and also gypsum rocks, which rocks areaffected by the application of heat so that they may be softened andremoved by water after being burned.

It becomes possible by the present mvention to prepare holes for thereception of large quantities of explosives with a comparatively smallexpense for drilling, and to concentrate the explosive'where it will bemost effective.

According to the practice now generally 1n vogue, in order to make useof the necessary quantities of explosives, and thereby obtamsatisfactory results, it is customary to drill either a large number ofsmall holes with close spacing or a proportionately smaller number oflarger ho es; the object being in each case to get the required amountof explosive as low down in the stone as is practicable, but with holesof this type it is necessary to distribute the explosive over aconsiderable length of the hole and less efficient results are obtainedthan if the explosive were more concentrated in the lower portion of thehole. The expense of drilling such a large number of holes or aproportionate number-of smaller holes is considerable, and the cost ofcarrying on extensive blasting operations in such manner becomes quiteburdensome in a large quarry.

Resort has been vsometimes had to the practice of squibbing or springingholes for blasting, that is to say, introducing and exploding therein asmall quantity of explosive for the purpose of enlarging the hole atsuch point in order to permit of the reception in such enlarged cavityof an increased amount of explosive, but such practices are recognizedas being extremely dangerous,

the material where the enlargement is sou ht to be made is not left insuch condition t at it may be removed, crevices are likely to be openedup in the squibbing operation, and it is impossible to tell how large aspace has thus been formed until after it has been filled with powder,dynamite, etc., when it is too late to make any change, and for theseand other reasonsit is recognized thatthe practice of squibbing holesfor blasting is dangerous, unsatisfactory and unreliable. Furthermore,the expense of carrying on blastin operations in this way is veryconsiderab e.

According to the present invention a hole is formed, as by drilling inthe ordinary way, and after the hole is drilled heat is applied thereinin the neighborhood where an enlargement is desired to be made, and inthe case of limestone and similar rocks this results in the burning ofthe rock to lime, which can be readily hydrated and washed out, as byapplying a stream of water for this purpose.

The application of heat may be accomplished in a variety of ways, but itis preferably applied by the introduction and combustion of solid fuelin the neighborhood where the heat is desired to be applied, provisionbeing made for supplying air to support combustion, and after theburning has been completed the decarbonated and chemically changedmaterial may be hydrated and flushed out as above described.

To supply the air for combustion I preferably introduce a pipe into thehole, the pipe having a diameter considerabl less than the diameter ofthe hole so as to leave an opening for the introduction of fuel.

neighborhood where the hole is desired to be enlarged and air issupplied thereto, a

Such pipe is of a length so that its lower end is in the a neighborhoodwhere the enlargement is desired to be made, preferably at the bottom ofthe hole, or ignited after being lowered into lace, as by means of atorch, air being it is used up and as there is room for the reception ofadditional fuel at the neighborhood of combustion. As the combustionprogresses, the ashes, of course, fall to the bottom and accumulate.When the ashes have filled the hole up as far as the enlargementis'desired the feeding of the fuel is discontinued, and when such fuelas remains is consumed the fire goes out and the air may be shut off.

The rate of combustion can, of course, be controlled by the air valvegoverning the amount of air admitted, since it is readily possible, iftoo much air is admitted, for the combustion to become too rapid and toburn away the pipe and overburn the stone; if limestone, making the limedifficult to slake. I preferably provide means whereby the progress ofcombustion can be observed from outside, and to this end I may provide apeep-hole with a transparent covering whereby the workman can look downthe air pipe and can judge by the appearance of the heated interiorthereof the rate of combustion, and if the pipe appears to be too hot hecan shut off a portion of the air, or if the redness of the heated pipeis not sufiiciently pronounced he can introduce additional air by meansof the air valve, as will be understood. The extent to which the rock isdecarbonated or otherwise changed in chemical make up about the drillhole, which, of course, determines the enlarged opening provided in thismanner, can be readily controlled by the operator as by varying theamount of fuel consumed, the rate of combustion and the length of timeduring which it is maintained, all of which,

'of course are under the complete control of the operator, who cantake'care of burning operations in a number of holes at the same time.With air supplied by pressure in the manner described the combustion isfrom the bottom. It will be understood that this situation may bereversed and the fuel burned from the top by drawing the air down thehole, as by connecting the air pipe to an exhauster, which creates asuction downward.

After the operation of burning has been carried on to an extentsuflicient for the requirements, and all the fuel consumed that isdesired to be used, the air is shut off.

Suitable connection can be made for the introduction of water, as by thepipe used for supplying air for combustion, or by another pipe, andwater is supplied thereby and permitted to escape from the upper end ofthe drill hole, carrying with it the ashes and the hydrated anddissolved material of the decarbonated rock, and finally the cleaningout may be completed as by means of pumps, such as ordinarily are usedfor cleaning out the sludge from the bottom of the drilled holes, and asare available in all quarries, the hole when finally cleaned of thesoluble or pasty hydrated decarbonated material bein greatly enlarged atthe point of burning an adapted to receive a quantity of explosive incompact concentrated form.

The burning of rock, as limestone or gypsum, takes place more readil inthe presence of moisture or steam, an ordinarily the moisture normallycontained in the rock which is transformed into steam during thecombustion is suflicient for supplying all needed moisture. For the mosteffective burning operation, however, in rocks where the moisturecontained is abnormally low, a steam or water pipe can be introducedalongside the air pipe, and such quantities of moisture as may be neededto most effectively perform the disintegration of the rock may beprovided, this being under the control of the operator as by means of asuitable valve or valves. If desired, steam or Water may be introducedthrough the air me. p Vitith the foregoing and related objects in view,my invention consists in the processes, operations and steps herein setforth and claimed.

In the accompanying drawing forming a part of this specification, I haveshown in the single figure thereof, for the purpose of making myinvention clearly understood, a cross-sectional view of rock having adrilled hole and apparatus therein in accordance with the presentinvention. In the said drawing, the rock in which the hole is made, andwhich is of a material such as limestone, gypsum or the like, and whichcan be calcined, is indicated by the reference numeral 1, and the.drilled hole, which is preferably of such small diameter as can be mosteffectively used and economically formed, is indicated by the referencenumeral 2.

3 indicates the air pipe which is introduced in the hole 2 andpreferably rests on the bottom thereof and is preferably provided with anumber of air holes 3 about the bottom so as to permit the escape of airaround the sides if, for any reason, the end should become clogged up.

4 indicates a coupling for the connection of an air pipe and the airvalve is indicated at 5. A lass covered peep-hole 6 is provided in t eends of the couplin site the pipe 3 so as to permit 0 servatlon of theinterior of the air ipe through the peep-hole if desired. e kindling, as

ieces of oil-soaked wood, which is placed 1n the hole, is indicated at7, and the fuel for supporting continued combustion, as coke, coal,charcoal or the like, is indicated at 8. Other combustible material as,for example, gas or oils or other liquid combustibles, may be used inplace of the solid com bustibles, as will be understood, and in suchcase may be introduced by meansof a suitable pipe which, however, is notillustrated and, as already stated, if additional moisture is required,a steam or water pipe may be provided for that purpose which, however,as in the case of the pipe for liquid combustibles, has not beenillustrated. The irregular line 9 indicates the cross-sectional outlineof burned or calcined part of the rock extending about the originalposition of the drilled hole .2, the size of such calcined portion andofthe resulting pocket formed when the calcined material is hydrated andremoved being, within reasonable limits, under the control of theoperator, who may vary the quantity of .fuel, the amount of air suppliedand the time during which the combustion is carried on to suit thecircumstances of the individual case.

As already stated, when the combustion has been completed and sufficientmaterial calcined, the calcined material may be hydrated and cleaned outwith water, and the final cleaning out may be completed as by means of asludge pump, leaving the enlarged opening ready to receive its charge ofexplosive.

When a wet hole is encountered, the water entering through crevices orcracks in the rock, it is only necessary to fill the hole in theneighborhood of the cavity with cement or plaster, and after thecrevices are scaled up thereby the cement or plaster can readily bedrilled through, or a suitable core may be inserted and the cement orplaster introduced around it, the core, as a piece of pipe,

being revolved while the plaster or cement is setting, and removed assoon as the plastic material has sufficiently set, either mode oftreatment leaving the crack or crevice sealed up and preventing theingress of water, and leaving a substantially dry hole for the burningprocess. If the cement or plaster is used to stop a crevice in theregion where the calcining takes place it becomes loose and is brokenout upon the swelling produced by the hydration of the calcined rock andcan be removed with the other material of the cavity. Such sealing maybe carried on much more conveniently and effectively with a smalldrilled hole masses therein, without enlarging, the large quantities ofexplosives needed.

This improved process effects numerous important economies; a saving ismade in the cost of drilling, the explosive has increased effectiveness,being arranged compactly in a chamber where its effect is concentrated,and a saving in explosives is thereb effected, and the spacing apart ofdrille holes may be increased, and generally effective blastingoperations can be carried on with greater economy,certainty andrecision.

W ile l have described and illustrated certain apparatus for carryingout my improved process, it is to be understood that the same isillustrated and described only 'for the purpose of making my inventionclear, an that my invention is not in any manner limited thereby.

Having thus described my invention, ll claim:

1. The process of opening a hole in calcinable rock, applying heatwithin said hole for calcining the rock, hydrating the calcinedmaterial, and removing the calcined hydrated material leaving anenlarged opening therein, substantially as set forth.

2. The rocess of forming a small diameter hole in calcinable rock,applying heat within said hole to the rock to calcine the same,hydrating the calcined material, and flushing it out with water,substantially as set forth.

3. The process which consists in mechanicall opening a small diameterhole in cal cina le rock, burning solid fuel and supplying air to suportcombustion therein, hydrating the calcined material, and flushing it outtogether with the solid roducts of combustion with water, thereby orminan enlargement or pocket in the region w ere combustion takes place,substantially as set forth. I

4. The process which consists in mechanically forming an opening incalcinable rock, supplying air and combustibles within said opening, andigniting such combustibles and supplying additlonal combustible materialto support combustion therein, and hydrating and removing the calcinedmaterial, thereby forming an enlargement of said opening sufiicient toaccommodate large uarliltities of explosives, substantially as set 'ort5. The process which consists in drilling '4, x 1, .oo,691

ing out the calcined material, and," finally hereunto set my hand, this8th day of Jancleaning out the hole with a sand ump uary, 1915. therebyforming an enlargement 0 said opening sufficient to accommodate largeWILLIAM MASON 4 8 uantities of explosives, substantially as set-Witnesses: orth. HENRY LANAHAN,

In testimony that I claim the foregoing, I MARY J. LAmmw.

